An X-ray CT apparatus causes an X-ray tube device (X-ray source) and an X-ray detector to revolve around an object with the X-ray tube device and the X-ray detector disposed to face each other, performs irradiation with X-rays in a plurality of rotation angle directions (views), then detects X-rays transmitted through the object for each view, and generates a tomogram of the object, based on detected projection data. In such an X-ray CT apparatus, the X-ray tube device and the X-ray detector are caused to revolve and a couch and a scanner gantry are caused to relatively move in a body-axial direction, and thereby helical scanning, in which scanning is performed in a spiral manner, is performed. In addition, in the X-ray CT apparatus, in order to improve spatial resolution of an image, for example a method of scanning by increasing the number of views per 360-degree rotation has been proposed.
However, a sampling rate or the like of the data collecting device is likely to be limited due to hardware limit or the like.
PTL 1 discloses a method of increasing, through calculation, the number of views of acquired projection data. In a technology of PTL 1, the projection data is interpolated within a selected view range and an interpolation view is generated. In general, the interpolation means that a value of a point as a target is obtained by using values of a plurality of points around the point as the target.